University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Vivian Isabell Remlinger
(2021):
Influence of pH on glyphosate adsorption onto allophane and halloysite.
Master / Diploma Thesis - Institut für Bodenforschung (IBF),
BOKU-Universität für Bodenkultur,
pp 62.
UB BOKU
obvsg
- Abstract:
- Glyphosate is a widely used herbicide which is currently being investigated due to its adverse effects on human health and the environment. In soils, glyphosate is known to strongly adsorb onto clay-sized minerals. Its adsorption onto soil components depends on the pH-value and the amount of organic carbon as well as the composition of Al- and Fe-oxyhydroxides and clay minerals and their specific surface area. Many clay-sized minerals have already been investigated regarding their adsorption behavior, but information on minerals commonly found in volcanic soils is still lacking. Recent studies have shown that glyphosate can be found in noticeable amounts in some volcanic soils. The aim of this study was to investigate pH-dependent adsorption of glyphosate onto allophane and halloysite. Synthetic allophane with two different initial Al:Si ratios (1.4 and 1.9) was used. For both minerals, adsorption of 5 different glyphosate concentrations was measured at 3 different pH values (5, 6 and 7). With rising Al:Si ratio, adsorption capacity (AC) increased. The AC of allophane was significantly higher compared to that of halloysite. A comparison with other studies showed that the amount of glyphosate adsorbed onto allophane was greater than onto other clay minerals and Al- and Fe-oxyhydroxides, especially at low pH. The AC of halloysite was greater than reported for most other clay silicates in the literature. At lower pH values, the AC of all three investigated minerals increased. The extraordinary high AC of allophanes might lead to a low mobility of glyphosate in allophane-containing soils and long-term use of glyphosate may lead to an accumulation of the herbicide in those soils. Findings about carcinogenicity and environmental toxicity of glyphosate are contradictory. Therefore, potential impacts on water and soil as well as ecosystems and biodiversity must be considered when applying glyphosate.
- Beurteilende(r): Gerzabek Martin